For network operators it is important to be able to distinguish between the traffic flows of subscribers, particularly in IP-based networks. Such a separation makes it possible for example for a network operator to approve for subscribers different authorizations for the quality and service quality of a data transmission which is referred to as “quality of service”—abbreviated to QoS—or to bill subscribers in accordance with different methods.
In the case of the GPRS mobile radio network it has been possible thus far for a subscriber to select an access point name (APN) which leads to different networks or to different handling of the traffic in the network of the corresponding operator. In such cases the access point name is connected to a so-called PDP (packet data protocol) context, which represents a layer 2 connection.
However, the method described is only used under some conditions by the network operators because it requires relatively high administration outlay.
Because of this methods are currently being introduced which, when a layer 2 connection (PDP context) and only one access point name is used, on the basis of the IP packets, which means on a layer 3 basis, allow the data traffic, meaning the data flows, to be distinguished. In order to identify data flows and their handling, a so-called “traffic plane handling function” is for example defined in this case. In the wider sense this thus involves a processing unit which can implement data flow-specific handling or functions. This handling can for example relate to the billing or to the QoS.
If only one access point name is used, this means that the entire traffic of a subscriber has to be routed via this processing unit in order to identify the individual data flows and for further handling of these flows such as, for example, billing, even if a part of the data traffic does not have to be handled in the processing unit. This would demand a high computing power for the processing unit, which would be very costly.
In addition, it is also very often the case that an overall layer 2 connection or a PDP context of a subscriber is to be subject to specific handling such as, for example, specific billing. In this case it is not necessary at the data flow level to identify each individual data flow of the relevant layer 2 connection because all the data flows of this layer 2 connection can be treated the same across the board.